Miller (Delay Modulation) encoding/decoding utility class. More...

#include <MillerCodec.h>

Inheritance diagram for pulsewire::MillerCodec:

Collaboration diagram for pulsewire::MillerCodec:

[legend]

Public Member Functions
	MillerCodec (Preamble &preamble)

CodecEnum	getCodecType () const override

size_t	getEdgeCount () const override
	Get the number of protocol symbols (bits, pulses, etc.) per encoded byte.

int	getEndOfFrameDelayUs () override

bool	getIdleLevel () const override
	Provides the initial ldle state (low or hith)

void	reset () override
	Reset the internal state of the codec.

size_t	encode (uint8_t byte, Vector< OutputEdge > &output) override
	Encode a byte using Miller encoding (byte-aligned).

size_t	flushEncoder (Vector< OutputEdge > &output) override
	Add termination edge at end of frame.

bool	decodeEdge (uint32_t durationUs, bool level, uint8_t &result) override
	Decode Miller encoding edge by edge.

virtual void	init (Preamble &detector, uint32_t shortPulseUs=600, uint32_t longPulseUs=1200, uint32_t toleranceUs=200)

virtual bool	begin (uint32_t bitFrequencyHz)
	initialization method for codecs that require setup before use (e.g., loading PIO programs, configuring state machines).

void	setPreamble (Preamble &preamble)
	Set the Preamble Detector object.

Preamble &	getPreamble ()
	Get the preamble detector associated with this codec.

void	setFrameSize (uint16_t size)
	Set the Frame Size.

uint16_t	getFrameSize () const
	Get the configured frame size.

const char *	name () const
	Get the name of the codec type as a string (e.g., "PulseDistance", "Manchester").

size_t	encodePreamble (Vector< OutputEdge > &output)

Protected Member Functions
bool	handleIdleGap (uint32_t durationUs, bool level, uint8_t &result)
	Handle idle gap detection and end-of-frame processing.

bool	handlePreamble (uint32_t durationUs, bool level)
	Handle preamble detection.

int	durationToHalfPeriods (uint32_t durationUs)
	Convert duration to half-periods (rounded to nearest).

void	decodeMiller (int hp, bool level)
	Decode Miller half-periods into bits.

void	decodeWhileExpectingMid (int hp)
	Decode when expecting mid-transition of a '1' bit.

void	decodeAtBoundary (int hp)
	Decode when at bit boundary (not expecting mid-transition).

bool	checkByteComplete (uint8_t &result)
	Check if a complete byte has been assembled.

void	pushBit (bool bit)
	Push a decoded bit into the receive buffer.

virtual void	encodeByte (uint8_t byte, std::vector< bool > &bits) const
	Encode a byte to protocol bitstream. Default implementation encodes to raw bits (MSB first), but can be overridden by protocols that require different bit formatting (e.g., Manchester). The output bits are stored in.

Protected Attributes
bool	_encLevel = true

uint8_t	_rxByte = 0

uint8_t	_rxBitPos = 0

bool	_rxExpectingMidTransition = false

CustomPreambleUs	_defaultPreamble

Preamble *	_preamble = &_defaultPreamble

uint16_t	_bitFrequencyHz = 0

uint32_t	_bitPeriodUs = 0

Vector< OutputEdge >	_decodeEdgeStream

volatile bool	_inFrame = false

uint16_t	_frameSize = 0

Detailed Description

Miller (Delay Modulation) encoding/decoding utility class.

Miller encoding rules (bit period = T):

'1': Transition in the MIDDLE of the bit period (T/2)
'0' after '0': Transition at the START of the bit period
'0' after '1': NO transition (level stays constant for full T)

This implementation uses BYTE-ALIGNED encoding where each byte is encoded independently. State is reset at byte boundaries to ensure clean decoding.

Definition at line 17 of file MillerCodec.h.

Constructor & Destructor Documentation

◆ MillerCodec()

pulsewire::MillerCodec::MillerCodec ( Preamble & preamble )

inline

Definition at line 20 of file MillerCodec.h.

Member Function Documentation

◆ begin()

virtual bool pulsewire::Codec::begin ( uint32_t bitFrequencyHz )

inlinevirtualinherited

initialization method for codecs that require setup before use (e.g., loading PIO programs, configuring state machines).

Reimplemented in pulsewire::RecorderCodec, pulsewire::DifferentialManchesterCodec, pulsewire::ManchesterCodec, pulsewire::PulseDistanceCodec, and pulsewire::PulseWidthCodec.

Definition at line 70 of file Codec.h.

◆ checkByteComplete()

bool pulsewire::MillerCodec::checkByteComplete ( uint8_t & result )

inlineprotected

Check if a complete byte has been assembled.

Returns: true if byte complete, with result set.

Definition at line 301 of file MillerCodec.h.

◆ decodeAtBoundary()

void pulsewire::MillerCodec::decodeAtBoundary ( int hp )

inlineprotected

Decode when at bit boundary (not expecting mid-transition).

Definition at line 275 of file MillerCodec.h.

◆ decodeEdge()

bool pulsewire::MillerCodec::decodeEdge	(	uint32_t	durationUs,
		bool	level,
		uint8_t &	result
	)

inlineoverridevirtual

Decode Miller encoding edge by edge.

Handles preamble detection using the base Codec's preamble logic, then interprets edge durations in terms of half-periods (hp):

hp=1 (0.5T): Half of a '1' bit (start or complete)
hp=2 (1T): One '0' bit with transition at boundary
hp=3 (1.5T): '0' followed by start of '1', OR '1' followed by '0'
hp=4 (2T): Two '0' bits, OR '1' + '0' + start of '1'

State machine tracks whether we're expecting the mid-transition of a '1'.

Implements pulsewire::Codec.

Definition at line 146 of file MillerCodec.h.

◆ decodeMiller()

void pulsewire::MillerCodec::decodeMiller	(	int	hp,
		bool	level
	)

inlineprotected

Decode Miller half-periods into bits.

Definition at line 232 of file MillerCodec.h.

◆ decodeWhileExpectingMid()

void pulsewire::MillerCodec::decodeWhileExpectingMid ( int hp )

inlineprotected

Decode when expecting mid-transition of a '1' bit.

Definition at line 246 of file MillerCodec.h.

◆ durationToHalfPeriods()

int pulsewire::MillerCodec::durationToHalfPeriods ( uint32_t durationUs )

inlineprotected

Convert duration to half-periods (rounded to nearest).

Definition at line 221 of file MillerCodec.h.

◆ encode()

size_t pulsewire::MillerCodec::encode	(	uint8_t	byte,
		Vector< OutputEdge > &	output
	)

inlineoverridevirtual

Encode a byte using Miller encoding (byte-aligned).

Miller encoding rules:

'1': Transition in the MIDDLE of the bit period (T/2)
'0' after '0': Transition at the START of the bit period
'0' after '1': NO transition (level stays constant for full T)

Each byte is encoded independently with state reset at boundaries. The encoder accumulates "pending" time at the current level and outputs edges when transitions occur.

Implements pulsewire::Codec.

Definition at line 50 of file MillerCodec.h.

◆ encodeByte()

virtual void pulsewire::Codec::encodeByte	(	uint8_t	byte,
		std::vector< bool > &	bits
	)		const

inlineprotectedvirtualinherited

Encode a byte to protocol bitstream. Default implementation encodes to raw bits (MSB first), but can be overridden by protocols that require different bit formatting (e.g., Manchester). The output bits are stored in.

Parameters

byte	The input byte to encode.
bits	Output buffer for encoded bits (protocol-specific format).

Definition at line 204 of file Codec.h.

◆ encodePreamble()

size_t pulsewire::Codec::encodePreamble ( Vector< OutputEdge > & output )

inlineinherited

Definition at line 157 of file Codec.h.

◆ flushEncoder()

size_t pulsewire::MillerCodec::flushEncoder ( Vector< OutputEdge > & output )

inlineoverridevirtual

Add termination edge at end of frame.

Adds a 2T pulse to ensure the receiver sees a final transition and can complete decoding any pending bits before timeout.

Reimplemented from pulsewire::Codec.

Definition at line 119 of file MillerCodec.h.

◆ getCodecType()

CodecEnum pulsewire::MillerCodec::getCodecType ( ) const

inlineoverridevirtual

Get the codec type (e.g., PulseDistance, Manchester) for this Codec instance.

Implements pulsewire::Codec.

Definition at line 22 of file MillerCodec.h.

◆ getEdgeCount()

size_t pulsewire::MillerCodec::getEdgeCount ( ) const

inlineoverridevirtual

Get the number of protocol symbols (bits, pulses, etc.) per encoded byte.

Returns: Number of protocol symbols per byte.

Implements pulsewire::Codec.

Definition at line 24 of file MillerCodec.h.

◆ getEndOfFrameDelayUs()

int pulsewire::MillerCodec::getEndOfFrameDelayUs ( )

inlineoverridevirtual

Provide the end of frame delay in microseconds for this protocol, used by RX driver to

Implements pulsewire::Codec.

Definition at line 26 of file MillerCodec.h.

◆ getFrameSize()

uint16_t pulsewire::Codec::getFrameSize ( ) const

inlineinherited

Get the configured frame size.

Definition at line 120 of file Codec.h.

◆ getIdleLevel()

bool pulsewire::MillerCodec::getIdleLevel ( ) const

inlineoverridevirtual

Provides the initial ldle state (low or hith)

Reimplemented from pulsewire::Codec.

Definition at line 28 of file MillerCodec.h.

◆ getPreamble()

Preamble & pulsewire::Codec::getPreamble ( )

inlineinherited

Get the preamble detector associated with this codec.

Returns: Reference to the Preamble instance used for preamble detection.

Definition at line 100 of file Codec.h.

◆ handleIdleGap()

bool pulsewire::MillerCodec::handleIdleGap	(	uint32_t	durationUs,
		bool	level,
		uint8_t &	result
	)

inlineprotected

Handle idle gap detection and end-of-frame processing.

Returns: true if a complete byte was output, false otherwise.

Definition at line 170 of file MillerCodec.h.

◆ handlePreamble()

bool pulsewire::MillerCodec::handlePreamble	(	uint32_t	durationUs,
		bool	level
	)

inlineprotected

Handle preamble detection.

Returns: true if we're in a frame and should process data, false to skip.

Definition at line 194 of file MillerCodec.h.

◆ init()

virtual void pulsewire::Codec::init	(	Preamble &	detector,
		uint32_t	shortPulseUs = `600`,
		uint32_t	longPulseUs = `1200`,
		uint32_t	toleranceUs = `200`
	)

inlinevirtualinherited

Used by IRTransceiver to initialize codec with protocol-specific parameters

Reimplemented in pulsewire::PulseWidthCodec, pulsewire::PulseDistanceCodec, and pulsewire::RecorderCodec.

Definition at line 63 of file Codec.h.

◆ name()

const char * pulsewire::Codec::name ( ) const

inlineinherited

Get the name of the codec type as a string (e.g., "PulseDistance", "Manchester").

Definition at line 135 of file Codec.h.

◆ pushBit()

void pulsewire::MillerCodec::pushBit ( bool bit )

inlineprotected

Push a decoded bit into the receive buffer.

Shifts the bit into _rxByte from the right (MSB first order). Ignores bits if byte is already complete (overflow protection).

Definition at line 318 of file MillerCodec.h.

◆ reset()

void pulsewire::MillerCodec::reset ( )

inlineoverridevirtual

Reset the internal state of the codec.

Reimplemented from pulsewire::Codec.

Definition at line 30 of file MillerCodec.h.

◆ setFrameSize()

void pulsewire::Codec::setFrameSize ( uint16_t size )

inlineinherited

Set the Frame Size.

Parameters

size

Definition at line 114 of file Codec.h.

◆ setPreamble()

void pulsewire::Codec::setPreamble ( Preamble & preamble )

inlineinherited

Set the Preamble Detector object.

Parameters

preamble

Definition at line 94 of file Codec.h.

Field Documentation

◆ _bitFrequencyHz

uint16_t pulsewire::Codec::_bitFrequencyHz = 0

protectedinherited

Definition at line 190 of file Codec.h.

◆ _bitPeriodUs

uint32_t pulsewire::Codec::_bitPeriodUs = 0

protectedinherited

Definition at line 191 of file Codec.h.

◆ _decodeEdgeStream

Vector<OutputEdge> pulsewire::Codec::_decodeEdgeStream

protectedinherited

Definition at line 192 of file Codec.h.

◆ _defaultPreamble

CustomPreambleUs pulsewire::Codec::_defaultPreamble

protectedinherited

Definition at line 188 of file Codec.h.

◆ _encLevel

bool pulsewire::MillerCodec::_encLevel = true

protected

Definition at line 330 of file MillerCodec.h.

◆ _frameSize

uint16_t pulsewire::Codec::_frameSize = 0

protectedinherited

Definition at line 194 of file Codec.h.

◆ _inFrame

volatile bool pulsewire::Codec::_inFrame = false

protectedinherited

Definition at line 193 of file Codec.h.

◆ _preamble

Preamble* pulsewire::Codec::_preamble = &_defaultPreamble

protectedinherited

Definition at line 189 of file Codec.h.

◆ _rxBitPos

uint8_t pulsewire::MillerCodec::_rxBitPos = 0

protected

Definition at line 334 of file MillerCodec.h.

◆ _rxByte

uint8_t pulsewire::MillerCodec::_rxByte = 0

protected

Definition at line 333 of file MillerCodec.h.

◆ _rxExpectingMidTransition

bool pulsewire::MillerCodec::_rxExpectingMidTransition = false

protected

Definition at line 335 of file MillerCodec.h.

The documentation for this class was generated from the following file:

src/pulse/codecs/MillerCodec.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ MillerCodec()

Member Function Documentation

◆ begin()

◆ checkByteComplete()

◆ decodeAtBoundary()

◆ decodeEdge()

◆ decodeMiller()

◆ decodeWhileExpectingMid()

◆ durationToHalfPeriods()

◆ encode()

◆ encodeByte()

◆ encodePreamble()

◆ flushEncoder()

◆ getCodecType()

◆ getEdgeCount()

◆ getEndOfFrameDelayUs()

◆ getFrameSize()

◆ getIdleLevel()

◆ getPreamble()

◆ handleIdleGap()

◆ handlePreamble()

◆ init()

◆ name()

◆ pushBit()

◆ reset()

◆ setFrameSize()

◆ setPreamble()

Field Documentation

◆ _bitFrequencyHz

◆ _bitPeriodUs

◆ _decodeEdgeStream

◆ _defaultPreamble

◆ _encLevel

◆ _frameSize

◆ _inFrame

◆ _preamble

◆ _rxBitPos

◆ _rxByte

◆ _rxExpectingMidTransition